This configuration shows the use of the FXT projection method. This method uses the fast multipole method implemented in FXTPACK for the projection between modal and nodal representations. A simple setup with a pulse in density that is convected through the periodic domain is used for this example.
The configuration is found in ateles.lua
:
-- Euler 3D setup with FXT method for projection. --
logging = { level = 10 }
-- ...the length of the cube
cubeLength = 2.0
-- the refinement level of the octree
level = 1
-- Transport velocity of the pulse in x direction.
velocityX = 100
-- global simulation options
simulation_name = 'gPulseDens_euler_fxt' -- the name of the simulation
sim_control = {
time_control = {
min = 0,
max = cubeLength/velocityX/16 -- final simulation time
}
}
-- Mesh definitions --
mesh = {
predefined = 'cube',
origin = {
(-1.0)*cubeLength/2.0,
(-1.0)*cubeLength/2.0,
(-1.0)*cubeLength/2.0
},
length = cubeLength,
refinementLevel = level
}
-- Equation definitions --
equation = {
name = 'euler',
isen_coef = 1.4,
r = 296.0,
material = {
characteristic = 0,
relax_velocity = {0, 0, 0},
relax_temperature = 0
}
}
-- (cv) heat capacity and (r) ideal gas constant
equation["cv"] = equation["r"] / (equation["isen_coef"] - 1.0)
-- Scheme definitions --
scheme = {
-- the spatial discretization scheme
spatial = {
name = 'modg',
m = 6
},
-- the temporal discretization scheme
temporal = {
name = 'explicitRungeKutta',
steps = 4,
-- how to control the timestep
control = {
name = 'cfl',
cfl = 0.8
}
}
}
projection = {
kind = 'fxt',
factor = 2.0
}
-- This is a very simple example to define constant boundary condtions.
initial_condition = {
density = {
predefined = 'gausspulse',
center = {0.0, 0.0, 0.0},
halfwidth = 0.20,
amplitude = 2.0,
background = 1.225
},
pressure = 100000,
velocityX = velocityX,
velocityY = 0.0,
velocityZ = 0.0,
}
-- Tracking
tracking = {
label = 'track_momentum_fxt',
folder = '',
variable = {'momentum'},
shape = {kind = 'canoND', object= { origin ={0., 0., 0.} } },
time_control = {
min = 0,
max = sim_control.time_control.max,
interval = sim_control.time_control.max/8.0
},
output = { format = 'ascii', ndofs = 1 }
}
Features used
Projection: fxt, Oversampling 2.0
Polynomial representation: Q
Filtering: --
Timestepping: explicitRungeKutta, 4 steps
Boundary conditions: --